There is a known image acquisition apparatus in which the optical properties of some pixels (hereinafter, referred to as phase-difference pixels) of an image acquisition device that acquires an image of a subject are made to differ from those of the other image-acquisition pixels, and the phase-difference pixels are used for focus detection, thereby eliminating a secondary optical system for focus detection (for example, see PTL 1).
A phase-difference pixel has a different aperture etc. from a normal image-acquisition pixel and obtains a different pixel value from the image-acquisition pixel; therefore, the continuity with surrounding pixel values is interrupted, and, if usual imaging processing is performed as is, the interrupted portion looks like a crack. To solve this problem, there is a known method for correcting the pixel value corresponding to the position of a phase-difference pixel through interpolation using the pixel values of surrounding image-acquisition pixels.
Furthermore, there is a known technique in which a plurality of low-resolution Bayer-array images that are acquired while shifting an image acquisition device are arranged in a high-resolution area, to obtain a higher-resolution image (hereinafter, referred to as pixel-shift super resolution) (for example, see PTL 2).